Approved by the Cancer.Net Editorial Board, 09/2016

With thrombocytopenia, a person's blood has an unusually low level of platelets.

Platelets are also called thrombocytes. They are made in bone marrow. This is the soft, spongy tissue found inside larger bones.

Platelets stop bleeding by helping clot blood and plug damaged blood vessels.

Thrombocytopenia happens in these cases:

  • The body does not make enough platelets.

  • The body loses platelets.

  • The body destroys platelets.

This side effect is common in people with cancer, especially for those receiving chemotherapy.

Signs and symptoms of thrombocytopenia

People with thrombocytopenia may experience some of these symptoms:

  • Unexpected bruising

  • Small purple or red spots under the skin. These are called petechiae.

  • Bleeding from the nose or gums

  • Heavier-than-usual menstrual periods in women

  • Black or bloody bowel movements

  • Red- or pink-colored urine

  • Bloody vomit

  • Severe headaches

  • Dizziness

  • Pain in the joints or muscles

  • Increased weakness

Tell your doctor immediately if you experience any of these symptoms. Often, symptoms do not occur until platelet levels are very low. For many patients, a blood test detects thrombocytopenia before symptoms occur.

Common causes of thrombocytopenia

Chemotherapy. Some types of chemotherapy and other medications damage bone marrow. This lowers its production of platelets. Typically, thrombocytopenia caused by chemotherapy is temporary. Rarely, chemotherapy may permanently damage some bone marrow cells that make platelets.

Antibodies attack platelets. The body makes specialized proteins called antibodies. They destroy substances that appear harmful to the body. These may include bacteria and viruses. However, this process sometimes works incorrectly, meaning the body produces antibodies that destroy healthy platelets.

Radiation therapy. Alone, this treatment usually does not cause thrombocytopenia. However, it may occur in these cases:

  • A significant amount of radiation is directed at the pelvis.
  • The patient is receiving chemotherapy at the same time.

Certain types of cancer. Cancer cells, such as leukemia or lymphoma cells, crowd out normal bone marrow cells.

Rare causes of thrombocytopenia

Cancer that spreads to the bone. For example, prostate or breast cancer that spreads to the bone may cause thrombocytopenia.

Spleen cancer. Excess platelets are stored in the spleen. Spleen cancer may cause the spleen to enlarge, which traps too many platelets.

Diagnosing thrombocytopenia

A blood test, called a platelet count, diagnoses thrombocytopenia. This test counts the number of platelets in a sample of blood.

These patients receive regular blood tests to look blood-related complications:

  • People with certain types of cancer.

  • People undergoing a cancer treatment type known to cause thrombocytopenia.

Treating thrombocytopenia

Treatment to relieve symptoms and side effects is an important part of cancer care. This approach is called supportive or palliative care.

Treatment for those receiving chemotherapy. People whose platelet counts drop may be able to switch to a lower chemotherapy dose. Or they may wait longer between chemotherapy cycles. Additionally, some patients may receive a drug called oprelvekin (Neumega). It helps prevent severe thrombocytopenia.

Treatment for those undergoing cancer surgery. The doctor may delay surgery until platelet counts return to a normal level. This reduces the risk of heavy bleeding.

Meanwhile, people with low platelet levels may receive a transfusion of platelet cells. This prevents spontaneous, heavy bleeding. However, transfused platelets only last about 3 days. And some patients may need multiple transfusions. Typically, platelets received through a transfusion do not last as long in patients who have received many transfusions.

Self-care for people with thrombocytopenia

These tips will help you avoid bleeding:

  • Ask your doctor before drinking alcohol or taking new medications. These can make bleeding problems worse.

  • Use an extra soft toothbrush, and don't floss if your gums bleed.

  • Blow your nose gently using a soft tissue.

  • Be careful using scissors, knives, needles, or other sharp tools.

  • Take steps to prevent burns while cooking.

  • Shave with an electric razor.

  • Avoid contact sports and other activities that might cause injury.

More Information

Side Effects

ASCO Answers Fact Sheet: Thrombocytopenia (PDF)

Bleeding Problems

Clotting Problems

Additonal Resource

Lab Tests Online: Platelet Count